Pygmy Rainbowfish

The pygmy rainbowfish (Melanotaenia pygmaea) belongs to the subfamily Melanotaeniinae.

Melanotaenia pygmaea thrive in tropical climates and typically live near the bottom of benthopelagic depths in Australia.

In this article, we’ll discuss the key characteristics of pygmy rainbowfish, their diet and habitat, and how to care for them.

Pygmy Rainbowfish Characteristics

Scientific Namethe Melanotaenia pygmaea
SpeciesM. pygmaea
Water Temperature23-28 degrees C (73-82 degrees F) range
pH Level6.8 to 7.2
Pygmy Rainbowfish Characteristics

Pygmy Rainbowfish Origin & Habitat

Melanotaenia pygmaea is native to Prince Regent River, West Kimberley district, and northwestern Australia.

They inhabit fast-flowing streams and tend to live in the deepest pools or bottom of waterfalls in the general vicinity.

These freshwater fishes prefer locations with primarily solid rock bottom and little vegetation in the water.

Pygmy Rainbowfish Conservation Status

The Pygmy Rainbowfish is in danger of becoming extinct and is listed as “Lower Risk: near threatened” on the IUCN Red List of Threatened Species.

What Are the Features of Pygmy Rainbowfish?


The male is brighter and more colorful than the female, with a shiny blue back and pale yellow fins. 

Also, there is a prominent mid-lateral stripe running down the male’s body.


Male Melanotaenia pygmaea grow to 5.5 cm total length (2.1 inches), while females only reach 3.5 cm max length (1.37 inches).

How to Care for Pygmy Rainbowfish?

a.Water Requirements

1. Water Quality

The Pygmy Rainbowfish is easy to keep as long as you avoid using chlorinated water in the aquarium.

However, if the tap water in your region has chlorine, you should use a de-chlorinator or a de-chlorinating technique before performing water changes.

To further ensure good water quality, you should perform regular water changes of 25% bi-weekly.

2. Water Temperature

Consistent water temperature will make your lovely fish feel more comfortable and prevent them from getting sick.

The ideal water temperature for the Pygmy Rainbowfish is between 23-28 degrees C (73-82 degrees F).

3. pH Level

When it comes to the ideal pH level, the Pygmy Rainbowfish can be somehow picky. The optimal pH level should be around neutral, from 6.8 to 7.2.  

b.Tank Setup

Replicating their natural habitat is the key to a successful tank setup for your rainbowfish.

Use smooth river rocks, driftwood, and plenty of live plants to create hiding spots and provide security for your fish.

Pygmy Rainbowfish Breeding

Like other rainbows, the Pygmy Rainbowfish is easy to breed in captivity. 

Your little fish will reach sexual maturity when they are just slightly longer than 2 cm (0.8 inches).

These guys breed in groups or in a harem. Therefore, you should set up a separate breeding tank consisting of one male and 2:3 females.

For egg-laying, you will need to add a suitable spawning medium, such as java moss or a spawning mop.

The spawning will happen in the morning. Thus, always check the aquarium for eggs every morning since adult fish can consume them quickly.

Once you notice the eggs, move the spawning medium to a separate container with sufficient aeration for better hatching rates.

If you keep the temperature around 25 degrees C (77 degrees F), the eggs will hatch within only two weeks.

After hatching, you can feed the fry infusoria and liquid fry food until they are large enough to devour newly hatched brine shrimp.

Last Words

We hope you enjoyed reading this article and now know everything about pygmy rainbowfish care.

These little fish are perfect for beginners and make a beautiful addition to any aquarium.

Do you have experience keeping pygmy rainbowfish? Let us know in the comments below!

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